Vincent SV 236MK issue. HELP!!!

PSOVLSK · March 6

I know the "Troubleshooting" forum is doesn't get a ton of traffic, so I hope this is seen.

My beloved Vincent is giving me problems. I suspect it's a tube issue, though I know nothing about tubes and have no real basis for that hypothesis.

I guess I should begin a good while ago when it would make a clicking sound when I turned it on. I knew it didn't sound good, but it didn't affect performance, so I never investigated the issue. Fast forward to about a week ago when I began hearing static coming out of my speakers (mainly the left speaker). It was very intermittent and could only be heard during quite passages if music was playing. I cleaned all of my connections and performed some cable management and the problem seemed to go away for a few days. On Sunday, it started again. I disconnected all of my equipment until only the Vincent and my speakers were connected and I still had the issue. Again, nothing major (I didn't think), but very annoying. Well, last night it became major. I turned on the Vincent and I didn't get the normal faint noise that I usually get from my speakers, but the static was a bit worse and was coming from both speakers. When I hit "play", nothing. I turned up the volume a little bit and I could hear the music, but it was very tinny...like sound was only coming from the tweeter. I disconnected the Vincent and hooked up the ol' reliable HK 7300 and the music returned.

Any ideas?

Keep in mind, I probably know just enough about equipment repair to really screw something up so...

marvda1 · March 6

A shot in the dark, did you check fuses?
You can go to Guitar Center to get new 12ax7 tubes, as you need backup tubes anyway.
Swap one of those side tubes with the front middle tube and see what happens.

PSOVLSK · March 6

I've done nothing yet. This happened late last night, so I haven't had a chance...plus I would have just popped the top and stared at the insides pretending to know what I was looking for.

Thanks. I'll try to swap those tubes tonight.

Clipdat · March 6

You can also quickly and easily get some 12ax7 tubes off Amazon Prime for testing. Hopefully it's just a tube issue.

PSOVLSK · March 6

Amazon is probably not the best place to buy tubes, but here's what they have:

TELEFUNKEN Elektroakustik Matched Pair of ECC83-TK | Black Diamond Series 9 Pin Replacement Vacuum Tube 12AX7 $155
Mullard 12AX7/ECC83, Matched Trio $105
New Gain Matched Trio (3) Tung-Sol Reissue 12AX7 ECC83 Tubes - $81
Electro-Harmonix 12AX7, Matched Trio $76
JJ 12AX7 / ECC83 Preamp Vacuum Tubes (Three Pack) $65
None of the above

Clipdat · March 6

JJ or EH will be fine for testing purposes.

(And in my experience nothing wrong with EH small signal tubes at all. YMMV but they sound pretty good to me.)

Slightly different model, but related/similar symptom: https://forums.stevehoffman.tv/threads/vincent-sv-237mk-integrated-amp-problem.784415/

PSOVLSK · March 7

Thanks for the help Drew and Marvin.

I just swapped one of the side tubes for the front tube and got good sound from my right speaker, so good news there.

I’ve got new tubes ordered, but I ordered the wrong thing. I thought the front tube was a 12ax7 and the other two were 6n1p, but all three tubes are 12ax7. Are they interchangeable? Remember, tube ignorant.

treitz3 · March 7

Whether or not they are a good set of tubes? Establish a baseline for evaluation/diagnosis.

No one ever said this hobby was cheap.....but it can be, based upon your attack plan to properly diagnose issues that arise.

Tom

Clipdat · March 7

PSOVLSK wrote: »

Thanks for the help Drew and Marvin.

I just swapped one of the side tubes for the front tube and got good sound from my right speaker, so good news there.

I’ve got new tubes ordered, but I ordered the wrong thing. I thought the front tube was a 12ax7 and the other two were 6n1p, but all three tubes are 12ax7. Are they interchangeable? Remember, tube ignorant.

Better to just return them and get the correct ones, imo. But I'll let the resident tube experts chime in too. @pitdogg2 @mhardy6647

PSOVLSK · March 7

Clipdat wrote: »

PSOVLSK wrote: »

Thanks for the help Drew and Marvin.

I just swapped one of the side tubes for the front tube and got good sound from my right speaker, so good news there.

I’ve got new tubes ordered, but I ordered the wrong thing. I thought the front tube was a 12ax7 and the other two were 6n1p, but all three tubes are 12ax7. Are they interchangeable? Remember, tube ignorant.

Better to just return them and get the correct ones, imo. But I'll let the resident tube experts chime in too. @pitdogg2 @mhardy6647

Agree. Cancelled my order (though I think the pair I don’t need has already shipped). I’ll wait for some recommendations before placing another order.

marvda1 · March 7

@PSOVLSK the 6n1p is similar to the Ecc88, 6dj8, 6922 types, and may substitute for these types in some high-level audio applications.
The correct Russian equivalent to the 6dj8/ecc88 is the 6n23p.

mhardy6647 · March 8

I don't have any good ideas off the top of my head.
The clicking is interesting. Is there a start-up relay in the preamp?
Unfortunately although I know of Vincent, I have zero knowledge of this particular component.
Does it have a normal potentiometer type volume control or electronic volume adjustment?
Does it have a mechanical "source selector" switch?
I will try to look it up anon.
Sorry!

mhardy6647 · March 8

EDIT: Oh, it's an integrated amp.

Static could always be noisy (dirty) pots or switches if so equipped.
If there are mechanical switches or potentiometers in the signal path, they can be cleaned with a good contact cleaner. There's an exhaustive primer, "the idiot's guide to using DeOxit" on audiokarma, e.g.
DeOxit is excellent but not the universal best choice for some switches and pots.
This amp is a hybrid(?).
Well, one

could always pop the top, make sure the tubes are properly seated... and, with the amplifier operating (and, of course, with due respect for -- but not fear of! -- the lethal voltages exposed), tap the tubes gently with a Tinkertoy or a wooden chopstick, and see if the static abates, gets better, or worse.
Use low volume levels, of course.

If it's dead at this point (???? I don't think it is, but I may have misread the OP), the issue could be with the power supply.

This amp doesn't appear to have everything mounted on one large, flimsy printed circuit board, but issues arising from flexing of the PC boards in modern vacuum tube components aren't uncommon.

Static-y noise can often arise from elderly carbon composition resistors (or silver-mica capacitors) but an amp like this is extremely unlikely to contain carbon comps and almost certain not to contain any silver-mica caps.

Any tantalum capacitors in it? If so, they're almost certainly past their 'use by' date. Tantalums aren't common in hifi equipment, but they're not unknown, either -- and they are justly notorious.

In their own way, they're even worse than electrolytics.

PSOVLSK · March 8

I think the problem has been identified as a bad tube, but I’ll find out for sure on Monday when my Amazon delivery arrives. Assuming that fixes the issue, I’m now interested in trying new tubes. I may start a new thread for help in that regard. Thanks for all the replies!!!

PSOVLSK · March 11

All is good. Received a new tube today (Genalex Gold Lion) and the music is back...improved even. My noise floor dropped considerably after adding the new tube. I always thought the hum/hiss was normal noise produced by the integrated, but I'm happy to find out it was the tube. I'm about to start a new thread to get advice on tubes, but I wanted to thank those who replied here. Much appreciated.

Vincent SV 236MK issue. HELP!!!

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